Do non-local correlations imply the existence of a preferred reference frame?

Do non-local correlations imply the existence of a preferred reference frame?

No. The only known non-local connection is the collapse of quantum entanglement, which is so limited in its effects and properties that in some interpretations of quantum mechanics there's no faster-than-light effect at all.

but if the correlations demonstrated by entanglement are indeed caused by some action at a distance, would that mean there is a preferred reference frame?

No. Because the populations are chosen and biased by their intent and their objectification.

Possibly not, since there are absolutely no observable physical effects from being the first one to observe the entangled system. If A observes, collapses it, and then B observes, this is physically indistinguishable from the viewpoint of either A or B if B observes, collapses it, and then A observes

So relativity of simultaneity still holds; there's no need to have either be objectively "first."

Does it matter who's first? Isn't it the case that when one entangled particle is observed, we "instantly" know the properties (say spin) of the other? Isn't the fact that it's a simultaneous collapse, regardless of who observes what first, something that challenges the notion of relative simultaneity?

>Cling to scientific realism in 2016.

No. Because we didn't know the properties of this one before observing.

That is what people mean by "entanglement transmits no information." The knowledge of the other particle's state has no physical effects at all on anything that actually happens to the other particle. Considered as an ensemble, they both "collapse" at once, but from each individual particle's perspective nothing has happened whatsoever.

Are you saying the uncertainty before collapse is epistemic?

That's the Consistent Histories / Quantum Bayesian interpretation.

It actually behaves almost exactly like epistemic uncertainty, and has clear analogies; the only reason it's not absolutely clear-cut is that in quantum mechanics, the possible states *interfere* with each other, altering the joint probabilities, until a measurement forces one of them to be definitely true- so there is a difference between quantum uncertainty and intuitive notions of uncertainty.

However, like epistemic uncertainty, information seems to be key.

In other interpretations, like Everett-Wheeler / Many-Worlds, the whole universe is in superpostion, and never truly collapses; "collapse" is not something that happens to the universe, but something that happens to *you*, as you go from seeing the superposition from the "outside" as it interferes with other wavefunctions, to seeing it from the *inside*, (at which point it decoheres rapidly and the wavefunction separates into non-interfering independent blobs of amplitude for each eigenstate).

What if the uncertainty is an objective feature of the world? If the wave functions of the entangled states are real? Would something not be transferred superluminally then?

Cannot use it to send a signal. As such, there's no way that it would produce observable ways to detect that preferred reference frame, and what's the difference between something that exists but is undetectable, and something that doesn't exist.

One comment. According to the tests of Bell's inequalities, it is not true that the results of these experiments are fixed beforehand. In a very real sense, the results are picked right when the measurement is done, and somehow communicated to the other particle, but again in such a way that we cannot use it to send a signal e.g. no possibility for FTL and no relativity causality problems.

That, or you have to go even weirder routes, like questioning counterfactual definiteness, or some even more IMO ridiculous ideas.

I think the "cannot be used for any practical purpose and thus is not worthy of discussion" line is a nice way to skirt around a serious foundational issue. If we accept that nonlocality is a feature of nature, then there are serious consequences to that. Consequences that should be reckoned with, at least on a conceptual level. Or, as you say, escape it through stranger interpretations, which inevitably lead to similar difficulties

Yes, but it's something that can't ever be detected or used to have any observable effects on events outside your light cone.

Which means the apparent superluminal effect has about as much physical meaning as your particular choice of coordinate systems.

Bohmian mechanics disagrees; it abandons locality but preserves determinism.

Many-Worlds is both deterministic and local: The pre-determined outcome of an observation is "all of them, but your subjective probability of being the "you" in a state corresponding to a.specific outcome is proportional to the square of the amplitude."

But it exists. What does this say about simultaneity?

>it is not true that the results of these experiments are fixed beforehand.

Not quite correct. It's more that all the possible outcomes appear to have some existence beforehand, and mutually interfere; but which one will be observed if enough information is extracted to point to a specific one appears to be unpredictable.

You're adopting way too strong of a classical realist position for my tastes, which is my objection.

Yes, I included abandoning locality in the "weirder" options. Many-worlds is even weirder still, and it's open to debate whether it's even an answer to the question as opposed to a dodge.

>Many-worlds is even weirder still, and it's open to debate whether it's even an answer to the question as opposed to a dodge.

I don't know; Many-Worlds seems like the closest thing available to an answer to me, but not a *complete* answer - it still doesn't explain why your subjective probabilities come out to the *square* of the amplitude, and without that it isn't a full interpretation.

This sort of stuff is why I think that the so-called Hard Problem of Consciousness has a little more relevance to the actual real world than people often think. Interpreting quantum mechanics seems to require understanding ourselves as minds operating within quantum mechanics, not classical observers outside of it; Many-Worlds has wavefunctions that never collapse but where brains and minds themselves go into superposition because they are part of it, QBism abandons the whole notion of objective reality and interprets quantum mechanics as a thing that happens to minds, Consistent Histories takes the form of a different way of reasoning about the world, essentially creating a sort of quantum epistemology.

Interpreting the why of quantum mechanics in a satisfying fashion requires us to be able to reason, from a set of physical laws, about what the world should look like to observers which are, themselves, physical systems subject to those laws.

I'm personally biased towards the spontaneous collapse line of theories for purely aesthetic reasons. On the bright side, we might actually be able to test in the near future if these ideas are right or wrong.

>Quantum Bayesian interpretation
It's shit and you know it
It's basically soloipsism